Analysis of a dolphin hunting technique suggests the
animals may be natural math geniuses.

Dolphins may use complex nonlinear mathematics when hunting,
according to a new study that suggests these brainy marine mammals could
be far more skilled at math than was ever thought possible before.

Inspiration for the new study, published in the latest Proceedings of
the Royal Society A, came after lead author Tim Leighton watched an
episode of the Discovery Channel's "Blue Planet" series and saw dolphins
blowing multiple tiny bubbles around prey as they hunted.

"I immediately got hooked, because I knew that no man-made sonar
would be able to operate in such bubble water," explained Leighton, a
professor of ultrasonics and underwater acoustics at the University of
Southampton, where he is also an associate dean.

"These dolphins were either 'blinding' their most spectacular sensory
apparatus when hunting -- which would be odd, though they still have
sight to reply on -- or they have a sonar that can do what human sonar
cannot�Perhaps they have something amazing," he added.

Leighton and colleagues Paul White and student Gim Hwa Chua set out
to determine what the amazing ability might be. They started by modeling
the types of echolocation pulses that dolphins emit. The researchers
processed them using nonlinear mathematics instead of the standard way
of processing sonar returns. The technique worked, and could explain how
dolphins achieve hunting success with bubbles.

The math involved is complex. Essentially it relies upon sending out
pulses that vary in amplitude. The first may have a value of 1 while the
second is 1/3 that amplitude.

"So, provided the dolphin remembers what the ratios of the two pulses
were, and can multiply the second echo by that and add the echoes
together, it can make the fish 'visible' to its sonar," Leighton told
Discovery News. "This is detection enhancement."

The second stage then involves subtracting the echoes from one
another, ensuring the echo of the second pulse is first multiplied by
three. The process, in short, therefore first entails making the fish
visible to sonar by addition. The fish is then made invisible by
subtraction to confirm it is a true target.

In order to confirm that dolphins use such nonlinear mathematical
processing, some questions must still be answered. For example, for this
technique to work, dolphins would have to use a frequency when they
enter bubbly water that is sufficiently low, permitting them to hear
frequencies that are twice as high in pitch.

"Until measurements are taken of wild dolphin sonar as they hunt in
bubbly water, these questions will remain unanswered," Leighton said.
"What we have shown is that it is not impossible to distinguish targets
in bubbly water using the same sort of pulses that dolphins use."

If replicated, the sonar model may prove to be a huge benefit to
humans. It might be able to detect covert circuitry, such as bugging
devices hidden in walls, stones or foliage. It could also dramatically
improve detection of sea mines.

"Currently, the navy uses dolphins or divers feeling with their hands
in such difficult conditions as near shore bubbly water, for example in
the Gulf," he said.

In terms of dolphin math skills, prior studies conducted by the
Dolphin Research Cetner in Florida have already determined that dolphins
grasp various numerical concepts, such as recognizing and representing
numerical values on an ordinal scale. Marine biologist Laela Sayigh of
the Woods Hole Oceanographic Institution said, "In the wild, it would be
very useful (for dolphins) to keep track of which areas were richer food
sources."

While dolphins are among the animal kingdom's most intelligent
animals, they are not likely the only math champs.

Parrots, chimpanzees and
even pigeons have been shown to have an advanced understanding of
numerical concepts. The studies together indicate that math ability is
inborn in many species, with number sense, mathematical skills and
verbal ability perhaps being separate talents in humans that we later
learn to combine.